Sofa



FIG. 1 is a front view of a sofa;

FIG. 2 is a back view of a sofa;

FIG. 3 is a side perspective view of a sofa;

FIG. 4 is a side perspective view of a sofa;

FIG. 5 is a top perspective view of a sofa; and,

FIG. 6 is a bottom view of a sofa.

The broken lines shown in the drawing disclosure are for illustrative purposes only and form no part of the claimed design. 

The ornamental design for a sofa, as shown and described. 